The Thumbwheel Switch as a Data Entry Device

Abstract

This study evaluated the speed and accuracy with which latitude and longitude coordinates can be entered into a computer by use of a thumbwheel switch unit. In addition, it determined the effect of flight gloves on thumbwheel operation, and compared two methods of using thumbwheels for entering coordinates. In the first method, one thumbwheel unit was used to enter both latitude and longitude of a given checkpoint before proceeding to the coordinates of the next checkpoint. In the second method, all latitude coordinates were entered sequentially, after which all longitude coordinates were entered in a similar manner. It was found that there were no significant differences in errors between gloved and ungloved operation, or between the two methods of entering coordinates. However, the two-unit method of entry was significantly faster than the one-unit method. It was concluded that the thumbwheel switch is suitable for use in entering navigational coordinates into an airborne computer.